This invention relates to engine ignitors, and more particularly, to an improved glow plug which minimizes flooding and/or hydraulic locking of single cylinder engines.
Numerous small sized internal combustion engines, comprise glow plugs which are designed to heat fuel introduced into internal combustion cylinders of an engine. Typically, the fuel may be atomized by an injection nozzle, mixed with air in a suction conduit and ignited by means of a glow plug.
Various skilled artisans have sought to improve conventional glow plugs by various means.
Matayoshi, et al., in U.S. Pat. No. 4,240,392, discloses one such improvement in which a glow plug can be electromagnetically or hydraulically moved relative to a fixed shell. This improvement was designed to provide a glow plug for a compression-ignited internal combustion engine having a swirl-producing free combustion chamber. The Matayoshi glow plug is stated to achieve an effective pre-heating of air in the pre-combustion chamber at cold starting of the engine, but at other times, occupy only a negligible volume thereby offering little obstruction to the production of a swirl of air in the pre-combustion chamber.
Nagai, et al. in U.S. Pat. No. 3,407,794, discloses a glow plug arrangement in which a stream of fuel is guided through an annular gap about the rear portion of a heated glow plug. The Nagai glow plug comprises an outer metal shell and a wire helix located in the shell and embedded in insulating material. An annular gap is provided in the region of the rear end for feeding liquid fuel in the annular gap. Accordingly, fuel fed into the annual gap will flow in an annular stream about the heated shell of the glow plug to be thus heated and completely evaporated without coming in contact with the wire helix so that the air fuel fixture forming in the region of the front end of the glow plug will be ignited by the latter.
U.S. Pat. No. 4,397,273, issued to Folkerts, discloses a retractable engine ignitor such as a glow plug for diesel engines. The inventive ignitor is arranged to be extended into an internal combustion engine when needed to aid starting and ignition. It is retracted from the combustion chamber when starting aid is no longer required in order to reduce interference with gas flow in the combustion chamber and the formation of particulates in the combustion process.
The patent to Sumner (U.S. Pat. No. 1,361,116) relates to a starting ignitor for an internal combustion engine. One of the stated objects of the Sumner invention is to provide an improved device for starting an engine to ensure prompt and certain ignition, until the heat generated by the burning of the fuel has heated up the normal igniting surfaces to a sufficient temperature to ignite the fuel. As shown in the patent drawings, the ignition member includes a plug which may be inserted and removed as necessary. As stated in the disclosure, when the engine is running under normal conditions, the valve (4) is closed and the electrical connection with starting plug is removed. By keeping the igniting member of the ignition plug removed from the free and open exposure to the heat, excessive heating thereof is prevented.
In addition to striving to improve flow characteristics of fuel introduced into internal combustion engines, a number of skilled artisans have recognized a significant need to correct the occurrence of flooding and/or hydraulic locking of single cylinder engines. This problem can occur when too much fuel is introduced into the combustion chamber, for instance, by excessive fuel injection during the ignition process. If the air-to-fuel ratio is too rich with fuel, heating alone of the fuel/air mixture will not necessarily produce combustion.
With conventional engine ignitors, one way of correcting flooding or hydraulically locking of the engine cylinder, is for the operator to simply leave the engine in a flooded condition, wait a sufficient period of time for the fuel mixture to hopefully evaporate from the engine cylinder, and thereafter, to return to re-attempt ignition of the engine by normal procedure.
Those skilled in the art, however, have recognized a significant need for a convenient means to vent flooded or hydraulically locked engine cylinders by a more reliable and convenient mechanism. The present invention fulfills these needs.